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1. Field of the Invention
The present invention relates to an apparatus and method for rapidly loading items onto vehicles. More specifically, the present invention relates to a method and apparatus for transferring simultaneously a quantity of items sufficient to load a vehicle to its capacity. A conveyor with a powered belt or powered rollers carrying the load is extended into the vehicle. The conveyor belt then slides out from underneath the load leaving the load within the vehicle as it retracts.
2. Prior Art.
Shipping is a major industry in this country. Thousands of airplanes, trains, ships, and trucks, transport millions of tons of all types of products across the nation and around the world. It is an industry that will never disappear. It is, therefore, a very competitive industry. Companies are constantly striving to increase the speed and efficiency with which they can transport products.
One of the bottlenecks in the shipping process is the loading and unloading of products from transportation vehicles. Most devices designed to load products into transportation vehicles only carry a relatively small number of items when compared to the total volume of a transportation vehicle.
For example, in the overland trucking industry, semi-trailers are often loaded by hand. Person""s are capable of carrying only a relatively small amount of material into a trailer and must be paid wages. This is very inefficient and very expensive.
Forklifts are sometimes employed to increase efficiency. Forklifts may carry more material than persons. However, because of the confined space within a trailer, it is very difficult to maneuver the forklift while in the trailer or other load carrying compartment. In addition, when using a forklift, the trailer must be precisely aligned with the docking bay so that the to forklift has an uninterrupted surface over which to drive. The inventors have identified another very significant difficulty in loading vehicles that greatly reduces the efficiency of the loading and unloading processes. Load carrying vehicles and compartments, such as trailers, vans and cargo ship load compartments all may only be accessed from one side. Only one forklift may load a truck at one time because it must enter and exit through the single door of the trailer. If a load of items to be transported could be stacked together from several directions, it would greatly accelerate the loading process. In addition, it would allow a wider variety of devices, such as cranes, to contribute to the loading process. This also holds true for the unloading process. All of the factors listed above make loading and unloading a trailer arduous, inefficient and slow. It can often take in excess of three hours to load or unload a semi-trailer.
Because of the long amount of time required to load and/or unload a trailer, distribution centers and warehouses often utilize several loading bays. This allows more trucks to be gradually loaded and unloaded at the same time. While this may increase the number of trucks that may be loaded, it also greatly increases the labor cost. Although shipping capacity is increased, efficiency is not.
In order to improve efficiency, some companies have utilized conveyor systems. Telescoping frames having a series of rollers are extended into the back of a trailer for unloading. Items are placed on the conveyor and given a push. Items then slide across the rollers to the other end of the conveyor frame and out of the trailer. Although the presence of the conveyor prevents use of a forklift, the speed with which a person may work is greatly increased. While use of a conveyor offers some advantages, it still has inherent disadvantages. It is still a very labor intensive process. The relatively confined area within the trailer limits the number of persons who may load or unload the trailer. In addition, items are prone to fall off either side of the conveyor. Those skilled in the art will be very familiar with these conveyor systems and their shortcomings.
These difficulties are not confined to the overland trucking industry. Load carrying compartments are utilized by trains, barges, cargo ships and airplanes. All aspects of the shipping industry would benefit from a more efficient method of transferring a load into a load carrying compartment.
It is therefore desirable to develop a way of rapidly and efficiently loading trucks.
It is also desirable to develop a method for rapidly and efficiently loading trucks without the need for precisely aligning trailers to their docking bays.
It is also desirable to circumvent the disadvantages caused by the relatively confined space and limited access of a trailer to allow rapid deposition of the load to be transported.
It is also desirable to develop a method for loading and unloading transportation vehicles that requires relatively few loading docks.
The present invention is an apparatus and method for rapidly transferring a load equal to the entire volume of a load carrying compartment at one time. A base frame is designed to be attached to the floor inside a loading dock. On top of the base frame rests an extensible conveyor. The extensible conveyor may be extended horizontally in a telescoping fashion such that it may be extended into a trailer or other load carrying compartment that has engaged the loading dock.
Preferably, the base frame is capable of a horizontal swiveling action. This allows the direction in which the conveyor is extended to be adjusted. This allows the extensible conveyor to extend into load carrying compartments that are not precisely aligned with the loading dock to which they are engaged. The extensible conveyor is capable of extending into the load carrying compartment such that it covers substantially the entire floor of the compartment.
Once the frame and conveyor are aligned with the load carrying compartment, the load is applied to the conveyor. The load transfer device is located on the inside floor of the docking bay and is accessible from all sides. This allows several men, forklifts and other loading systems to apply the load to the extensible conveyor from all directions. A load substantially equal to the carrying capacity of the load carrying compartment is applied to the extensible conveyor prior to being extended into the compartment. The conveyor is then extended into the load carrying compartment. The extensible conveyor is then slowly retracted so that it eventually comes to rest in its original position, completely on top of the fixed frame. As the conveyor retracts, the conveyor belt is activated in a direction opposite to the motion of retraction. The conveyor belt moves at the same rate of speed as the retraction of the extensible conveyor. In this fashion, the load is slid off the extensible conveyor such that it remains within the load carrying compartment. When the extensible conveyor has been entirely retracted onto the fixed frame, the entire load has been completely placed in the load carrying compartment.
This method of loading compartments offers many advantages to current methods. Because the extensible conveyor is accessible from all sides including above it, a variety of machines as well as persons may stack items that comprise the total load simultaneously. Using current methods, only a few persons or a single forklift may enter a load compartment such as a trailer at one given time. Conveyors have only limited access to the inside of the compartment, while cranes generally have no access whatsoever. Use of an extensible conveyor allows items to be stacked using conveyors, cranes, forklifts and other devices known to those skilled in the art.
The present load transfer device and method allows several persons and devices to stack the load of products to be transported because the extensible conveyor is accessible from every direction. It allows a vehicle or load carrying compartment to be loaded in a fraction of the amount of time it takes to load a vehicle using current methods.
Because a load may be deposited into a load carrying compartment significantly more rapidly, fewer loading docks are required to load and transport the same amount of materials. A significant amount of time is also saved because compartments such as trailers no longer need to be accurately and precisely aligned with the docking bay. The swiveling action of the frame allows trailers and other compartments to be aligned less accurately and therefore much more easily.
The present invention may be designed in any variety of sizes, depending upon the desired application. Smaller versions of the invention may be used for loading and unloading vans and package cars. Larger embodiments of the invention, may be used to load trailers, trains, airplanes, cargo ships and compartments used therein.
The frame and conveyor apparatus may be aligned with the load carrying compartment using lasers, extensible rods, optical alignment tools and other methods well known to those skilled in the art.
It is also preferable to include a number of safety devices on the invention. Emergency shut-off switches may be located at a variety of points on the invention. In addition, sensors at the front of the extensible conveyor may be used to detect a persons within the load compartment and stop the invention so as not to crush those persons.
Various alignment tools may also be used to insure that the load stacked on the extensible conveyor will fit into the load carrying compartment.
It is therefore an object of the present invention to provide an apparatus and method for rapid, efficient loading or a load carrying compartment.
It is another object of the present invention to provide an apparatus and method for circumventing the difficulties and limitations imposed by the restricted access to existing load carrying compartments.
It is another object of the present invention to provide an apparatus and method for inserting a load substantially equal to the total carrying capacity of a load carrying compartment simultaneously.